The Crystal Structure of Human Argonaute2

By N. Schirle, I. MacRae. Science, 2012

684 citations recorded by the source corpus.

Human Argonaute Revealed RNA interference (RNAi) is mediated by Argonaute (Ago) proteins, which bind small regulatory RNAs that have sequence complementarity to target RNAs destined to be silenced. The structure of bacterial homologs of the Ago proteins, and fragments of eukaryotic Ago proteins, have provided initial insights into Ago function. Now, Schirle and MacRae (p. 1037, published online 26 April; see the Perspective by Kaya and Doudna) have determined the structure of the full-length human Ago protein bound to a single-stranded (ss) guide RNA. Within the bilobed structure, eight nucleotides of the ssRNA are visibly positioned in the RNA-guide, strand-binding site. The “seed” region of the ssRNA has its Watson-and-Crick base edges exposed to solvent, likely aiding target recognition. The location of two free tryptophans in the Piwi domain suggests a possible recruitment site for Ago-interacting proteins. The structure of the core protein of the human RNA interference machinery is determined at high resolution. Argonaute proteins form the functional core of the RNA-induced silencing complexes that mediate RNA silencing in eukaryotes. The 2.3 angstrom resolution crystal structure of human Argonaute2 (Ago2) reveals a bilobed molecule with a central cleft for binding guide and target RNAs. Nucleotides 2 to 6 of a heterogeneous mixture of guide RNAs are positioned in an A-form conformation for base pairing with target messenger RNAs. Between nucleotides 6 and 7, there is a kink that may function in microRNA target recognition or release of sliced RNA products. Tandem tryptophan-binding pockets in the PIWI domain define a likely interaction surface for recruitment of glycine-tryptophan-182 (GW182) or other tryptophan-rich cofactors. These results will enable structure-based approaches for harnessing the untapped therapeutic potential of RNA silencing in humans.

Subfields: Cardiology and Cardiovascular Medicine, Molecular Biology

View Paper: https://www.semanticscholar.org/paper/806c5fa769120c1f204402573965f15bb660a552

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In Cardiology and Cardiovascular Medicine

David P. Bartel

In Molecular Biology

Citations in the corpus

Molecular mechanisms of RNA interference (2013, neutral): “Helix 7 has been proposed to facilitate passenger strand release and/or to perform readout of miRNA target recognition that would be coupled to its necessary reorientation upon target binding (77).”
Predicting effective microRNA target sites in mammalian mRNAs (2015, background): “In contrast, the seed backbone is pre-organized to favor A-form pairing, with bases of nucleotides 2–5 accessible to nucleate pairing ( Nakanishi et al., 2012 ; Schirle and MacRae, 2012 ).”
Metazoan MicroRNAs (2018, background): “…α–helix 7 leaves only miRNA nucleotides 2–5 suitably preorganized and accessible for the target search (Elkayam et al., 2012; Nakanishi et al., 2012; Schirle and MacRae, 2012) (Figure 6A, step 1), and single-molecule analyses demonstrate that this sub-seed segment is indeed most critical for…”
microRNAs in action: biogenesis, function and regulation (2023, background): “Argonaute–miRNA– target structures reveal a structural basis for such pairing, as the miRNA seed is pre-arranged into an A-form conformation that is primed for base-pairing with its target mRNA 18–20 .”
The Structure of Human Argonaute-2 in Complex with miR-20a (2012, neutral): “The structure of hAgo2 in complex with a heterogeneous mixture of bound RNAs of different lengths was published (Schirle and Macrae, 2012).”